1. Field of the Invention
The invention relates to the detection and amplification of the outputs from the sense windings of a memory arrangement, and more particularly to detecting the output from the sense windings of a plurality of ring core modules each of which has a plurality of word wires.
2. Description of the Prior Art
The invention was developed for the system shown in U.S. Pat. No. 3,767,863 issued Oct. 23, 1973 by Borbas et al for a Communication Switching System with Modular Organization and Bus, hereinafter referred to as the System S2 patent.
A ring core memory arrangement is described in U.S. Pat. No. 3,487,173 issued Dec. 30, 1969 by Duthie et al for a Small Exchange Stored Program Switching System, hereinafter referred to as the System S1 patent. The memory and sense amplifier of the system is shown in U.S. Pat. No. 3,587,070 issued June 22, 1971 by Thomas for a Memory Arrangement having both Magnetic-Core and Switching-Device Storage with a Common Address Register, hereinafter referred to as the S1 Memory patent.
The sense amplifier (designated a read amplifier) in the S1 Memory patent had individual inputs for each sense winding output of the core and this allowed a high noise level. The input and output are both single sided and there are five summing inputs, one for each core. This produced a noise prone configuration since five inputs are summed at the amplifier and each has up to fifteen feet of wire on it and also one wire of each pair from the core output is AC coupled to ground and is thus not balanced. Another problem with the S1 sense amplifier was that if one core was shorted to ground both outputs would be reduced, thereby affecting both systems. Further, the output circuit of the amplifier was not protected from damage by shorts to ground or from the voltage supply.